Authorities have detained 341 foreign nationals working illegally in the first crackdown targeting asylum seekers in areas under the jurisdiction of the Tokyo and Nagoya immigration bureaus, an effort aimed at curbing alleged abuse of Japan's refugee system.

The Justice Ministry announced Tuesday that of the foreign nationals detained in the crackdown conducted between Nov. 6 and Dec. 1, 94 men and women were awaiting the government's decision on whether to grant them refugee status. Others included visa overstayers and people engaged in activities other than those permitted under their visa status.

"The number of applications for asylum with an aim to secure jobs, which we can't approve of, is on the rise, so we need to adopt stricter measures while processing those applications," ministry official Hiroshi Kimizuka told reporters. "But we also need to strengthen efforts in detecting people who successfully went through the screening process and have been working illegally (in Japan)."